U.S. patent application number 12/117167 was filed with the patent office on 2009-11-12 for on-board water addition for fuel separation system.
This patent application is currently assigned to FORD GLOBAL TECHNOLOGIES, LLC. Invention is credited to Mark Allen Dearth, Thomas G. Leone.
Application Number | 20090277418 12/117167 |
Document ID | / |
Family ID | 41265851 |
Filed Date | 2009-11-12 |
United States Patent
Application |
20090277418 |
Kind Code |
A1 |
Leone; Thomas G. ; et
al. |
November 12, 2009 |
ON-BOARD WATER ADDITION FOR FUEL SEPARATION SYSTEM
Abstract
A fuel delivery system for an internal combustion engine
including a fuel tank, a membrane dividing the fuel tank into at
least a first and second portion, the membrane preferentially
diffusing a substance from a mixture, the substance having an
increased knock suppression relative to the mixture, and a
controller adjusting delivery of condensed water to the tank
responsive to an operating condition.
Inventors: |
Leone; Thomas G.;
(Ypsilanti, MI) ; Dearth; Mark Allen; (Dearborn,
MI) |
Correspondence
Address: |
ALLEMAN HALL MCCOY RUSSELL & TUTTLE, LLP
806 S.W. BROADWAY, SUITE 600
PORTLAND
OR
97205
US
|
Assignee: |
FORD GLOBAL TECHNOLOGIES,
LLC
Dearborn
MI
|
Family ID: |
41265851 |
Appl. No.: |
12/117167 |
Filed: |
May 8, 2008 |
Current U.S.
Class: |
123/25R ;
123/25J; 123/575; 123/578 |
Current CPC
Class: |
F01N 2240/22 20130101;
F02M 25/0227 20130101; F02M 37/0094 20130101; Y02T 10/20 20130101;
F02M 43/00 20130101; F02M 25/14 20130101; F01N 3/005 20130101; Y02T
10/121 20130101; Y10T 137/2499 20150401; Y02T 10/12 20130101; F02M
25/0228 20130101 |
Class at
Publication: |
123/25.R ;
123/575; 123/578; 123/25.J |
International
Class: |
F02M 25/028 20060101
F02M025/028; F02B 47/02 20060101 F02B047/02; F02M 43/00 20060101
F02M043/00 |
Claims
1. A fuel delivery system for an internal combustion engine
comprising: a fuel tank; a membrane dividing the fuel tank into at
least a first and second portion, the membrane preferentially
diffusing a substance from a mixture, the substance having an
increased knock suppression relative to the mixture; and a
controller adjusting delivery of condensed water to the tank
responsive to an operating condition.
2. The fuel delivery system of claim 1 wherein the mixture includes
gasoline and an alcohol, and where the membrane diffuses alcohol
preferentially from gasoline.
3. The fuel delivery system of claim 1 wherein the controller
reduces delivery of water responsive to reduced temperature.
4. The fuel delivery system of claim 1 wherein the operating
condition includes an amount of water in the second portion of the
tank.
5. The fuel delivery system of claim 1 further comprising a
battery, the operating condition including a battery state of
charge.
6. The fuel delivery system of claim 1 wherein the condensed water
is collected from an exhaust of the engine.
7. The fuel delivery system of claim 1 wherein the operating
conditions include a fuel tank level of one of the first and second
portions.
8. The fuel delivery system of claim 1 wherein the first portion
contains the mixture.
9. The fuel delivery system of claim 1 wherein the condensed water
is gathered from an air conditioning system, and where the
controller adjusts operation of the air conditioning system to
adjust delivery of the condensed water.
10. The fuel delivery system of claim 1, wherein the controller
further adjusts delivery of condensed water by adjusting a
pump.
11. The fuel delivery system of claim 1, wherein the controller
further adjusts delivery of condensed water by adjusting a flow of
air over a condenser.
12. A fuel delivery system for an internal combustion engine
comprising: a fuel tank; a membrane dividing the fuel tank into a
first portion enclosing a blended fuel mixture and a second
portion, the blended fuel mixture including gasoline and ethanol; a
first injector configured to receive fuel from the first portion of
the fuel tank; a second injector configured to receive fuel from
the second portion of the fuel tank; and a controller configured to
adjust the amount of condensed water in the second portion of the
fuel tank in response to an operating condition.
13. The fuel delivery system of claim 12 wherein the operating
condition includes an ambient temperature.
14. The fuel delivery system of claim 12 wherein the operating
condition includes a concentration of water in the second
portion.
15. The fuel delivery system of claim 12 wherein the operating
condition includes a battery condition.
16. The fuel delivery system of claim 12 wherein the first injector
is configured to provide port fuel injection and the second
injector is configured to provide direct fuel injection.
17. The fuel delivery system of claim 12 wherein the membrane is
flexible, the membrane configured to flex and passively adjust a
volume of the first or second portions of the fuel tank.
18. A fuel delivery system in an internal combustion engine of a
vehicle, comprising: a fuel tank; a battery; a flexible membrane
dividing the fuel tank into at least a first and second portion; a
port injector coupled to the first portion; a direct injector
coupled to the second portion; a water condensate system coupled to
the second portion, the water condensate system including an
electrically driven actuator configured to adjust delivery of water
condensate to the second portion of the fuel tank; and a controller
configured to adjust the actuator in response to an engine
temperature and concentration of water in the second portion of the
fuel tank.
19. The fuel delivery system of claim 18 wherein the actuator is a
pump coupled to a condenser included in the water condensate
system.
20. The fuel delivery system of claim 18 wherein the actuator is a
fan configured to direct air over a condenser included in the water
condensate system.
21. The fuel delivery system of claim 18 wherein the control
further adjusts the actuator in response to a fuel level and a
state of charge of the battery.
Description
BACKGROUND/SUMMARY
[0001] Engines may operate using a plurality of different
substances, which may be separately delivered, or delivered in
varying ratios, depending on operating conditions. For example, an
engine may use a first fuel (ethanol) and a second fuel (gasoline),
each with different knock suppression abilities, to reduce engine
knock limitations while improving overall fuel economy. As another
example, an engine may use fuel injection and water injection.
[0002] Various approaches may be used to store different substances
on-board a vehicle. For example, the different substances may be
stored separately in different storage tanks, and thus filled
separately. Alternatively, different substances may be stored in a
mixed state, and then separated on-board the vehicle to enable
individual control of delivery to the engine.
[0003] One approach which allows ethanol to be separated from a
blended fuel mixture is described in US 2007/0221163. In US
2007/0221163 a separating device, fluidly coupled downstream of the
fuel tank, is used to separate ethanol from a blended fuel mixture.
A series of injectors are used to supply the separated fuel to a
combustion chamber in the engine. Water may be provided to the
separating device to aid in the separation of the ethanol from the
blended fuel mixture. The water is recovered from the engine
exhaust.
[0004] The inventor has recognized several disadvantages with this
approach. For example, depending on the conditions and the amount
of water in the mixture, the mixture may be subject to freezing.
Freezing may in turn degrade separation, as well as various
components of the system.
[0005] As such, in one approach, a fuel delivery system for an
internal combustion engine including a fuel tank, a membrane
dividing the fuel tank into at least a first and second portion,
the membrane preferentially diffusing a substance from a mixture,
the substance having an increased knock suppression relative to the
mixture, and a controller adjusting delivery of condensed water to
the tank responsive to an operating condition.
[0006] In this way, not only is it possible to adjust the rate of
separation of a knock suppressing substance via control of
condensed water delivery, but in addition it is possible to reduce
risks of freezing. As one example, the delivery of condensed water
can be reduced under conditions where ambient temperatures are
decreased, even when increased water is needed to aid
separation.
BRIEF DESCRIPTION OF DRAWINGS
[0007] FIG. 1 shows a schematic depiction of one cylinder in the
internal combustion engine.
[0008] FIG. 2 shows a schematic depiction of a vehicle's exhaust,
air conditioning, and fuel delivery systems.
[0009] FIG. 3 shows a first example method for adjusting water
provided to the fuel tank.
[0010] FIG. 4 shows a second example method for adjusting water
provided to the fuel tank.
DETAILED DESCRIPTION
[0011] A vehicle's engine may operate with a plurality of
substances including different fuels, knock suppressing substances,
etc. For example, an engine may operated with different fuels
having different knock suppressing capabilities, either due to an
injection type (direct or port injection, for example), or due to
fuel properties. For example, direct injection may provide
increased knock suppression compared with port injection. As
another example, direct injection of a fuel having an increased
alcohol concentration (as compared to another fuel) may also
provide increased knock suppression. As still another example,
water injection may also be used to affect engine combustion and
reduce knock under some conditions. The water may be injected via
one or more injectors, or mixed with one or more fuels in varying
concentrations.
[0012] As described herein, various approaches are described for
advantageously using a membrane to selectively separate one or more
substances from a mixture. In one particular example, the membrane
selectively transfers an alcohol (e.g., ethanol) from a mixture of
gasoline and alcohol on one side, to water (or a water/alcohol
mixture) on the other side. Further, the transfer rate across the
membrane may be adjusted by, for example, selectively delivering
additional water to the water/alcohol mixture. In this way, the
increased knock suppression of the water/ethanol mixture may be
separately delivered to the engine from the gasoline/alcohol
mixture to thereby obtain increased engine performance while
reducing knock limitations.
[0013] Referring now to FIG. 1, it shows a schematic diagram
showing one cylinder of multi-cylinder engine 10, which may be
included in a propulsion system of an automobile. Engine 10 may be
controlled at least partially by a control system including
controller 12 and by input from a vehicle operator 132 via an input
device 130. In this example, input device 130 includes an
accelerator pedal and a pedal position sensor 134 for generating a
proportional pedal position signal PP. Combustion chamber (i.e.
cylinder) 30 of engine 10 may include combustion chamber walls 32
with piston 36 positioned therein. Piston 36 may be coupled to
crankshaft 40 so that reciprocating motion of the piston is
translated into rotational motion of the crankshaft. Crankshaft 40
may be coupled to at least one drive wheel of a vehicle via an
intermediate transmission system. Further, a starter motor may be
coupled to crankshaft 40 via a flywheel to enable a starting
operation of engine 10.
[0014] Combustion chamber 30 may receive intake air from intake
manifold 44 via intake passages 42 may exhaust combustion gases via
exhaust passage 48. Intake manifold 44 and exhaust passage 48 can
selectively communicate with combustion chamber 30 via respective
intake valve 52 and exhaust valve 54. In some embodiments,
combustion chamber 30 may include two or more intake valves and/or
two or more exhaust valves.
[0015] Intake valve 52 may be controlled by controller 12 via a
valve actuator. Similarly, exhaust valve 54 may be controlled by
controller 12 via another valve actuator. Additionally, both the
intake and exhaust valves may be adjusted via a common actuator.
For example, during some conditions, controller 12 may operate the
valve actuator to vary the opening and/or closing of the respective
intake and/or exhaust valves. The valve actuator may include one or
more of electromagnetic valve actuators for operating cam-less
valves, a cam profile switching (CPS) actuator, variable cam timing
(VCT) actuator, a variable valve timing (VVT) actuator and/or a
variable valve lift (VVL) actuator to vary valve operation.
[0016] Fuel injector 66 is shown coupled directly to combustion
chamber 30 for injecting fuel directly therein in proportion to the
pulse width of signal FPW received from controller 12 via
electronic driver 68. In this manner, fuel injector 66 provides
what is known as direct injection of fuel into combustion chamber
30. The fuel injector may be mounted in the side of the combustion
chamber or in the top of the combustion chamber, for example. In
this example, fuel may be delivered to fuel injector 66 by a fuel
delivery system, shown in FIG. 2 discussed in more detail herein.
Specifically fuel injector 66 may be included in fuel injectors
244, shown in FIG. 2. In other examples, other suitable fuel
delivery systems may be utilized.
[0017] Additionally, in this example, a fuel injector 67 is
arranged in a port of intake manifold 44 in a configuration that
provides what is known as port injection of fuel into the intake
port upstream of combustion chamber 30. Further in this example,
fuel injectors 254, shown in FIG. 2, may include port fuel injector
67.
[0018] Continuing with FIG. 1, Intake passage 42 may include a
throttle 62 having a throttle plate 64. In this particular example,
the position of throttle plate 64 may be varied by controller 12
via a signal provided to an electric motor or actuator included
with throttle 62, a configuration that is commonly referred to as
electronic throttle control (ETC). In this manner, throttle 62 may
be operated to vary the intake air provided to combustion chamber
30 among other engine cylinders. The position of throttle plate 64
may be provided to controller 12 by throttle position signal TP.
Intake passage 42 may include a mass air flow sensor 120 and a
manifold air pressure sensor 122 for providing respective signals
MAF and MAP to controller 12.
[0019] Ignition system 88 can provide an ignition spark to
combustion chamber 30 via spark plug 92 in response to spark
advance signal SA from controller 12, under select operating modes.
Ignition system may include a battery capable of delivering
electrical power to the spark plug and other systems in the
vehicle. Though spark ignition components are shown, in some
embodiments, combustion chamber 30 or one or more other combustion
chambers of engine 10 may be operated in a compression ignition
mode, with or without an ignition spark.
[0020] Exhaust gas sensor 126 is shown coupled to exhaust passage
48 upstream of emission control device 70. Sensor 126 may be any
suitable sensor for providing an indication of exhaust gas air/fuel
ratio such as a linear oxygen sensor or UEGO (universal or
wide-range exhaust gas oxygen), a two-state oxygen sensor or EGO, a
HEGO (heated EGO), a NOx, HC, or CO sensor. Emission control device
70 is shown arranged along exhaust passage 48 downstream of exhaust
gas sensor 126. Emission control device 70 may be a three way
catalyst (TWC), NOx trap, various other emission control devices,
or combinations thereof.
[0021] A condenser 256, discussed in more detail herein, may be
fluidly coupled downstream of the emission control device. Under
some conditions water may be condensed in the condenser, and
removed from the condenser via a pump 266, shown in FIG. 2.
[0022] Again referring to FIG. 1, controller 12 is shown in FIG. 1
as a microcomputer, including microprocessor unit 102, input/output
ports 104, an electronic storage medium for executable programs and
calibration values shown as read only memory chip 106 in this
particular example, random access memory 108, keep alive memory
110, and a data bus. Controller 12 may receive various signals from
sensors coupled to engine 10, in addition to those signals
previously discussed, including measurement of inducted mass air
flow (MAF) from mass air flow sensor 120; engine coolant
temperature (ECT) from temperature sensor 112 coupled to cooling
sleeve 114; a profile ignition pickup signal (PIP) from Hall effect
sensor 118 (or other type) coupled to crankshaft 40; throttle
position (TP) from a throttle position sensor; a key position from
ignition sensor 123; and absolute manifold pressure signal, MAP,
from sensor 122. Engine speed signal, RPM, may be generated by
controller 12 from signal PIP. Manifold pressure signal MAP from a
manifold pressure sensor may be used to provide an indication of
vacuum, or pressure, in the intake manifold. Note that various
combinations of the above sensors may be used, such as a MAF sensor
without a MAP sensor, or vice versa. As described above, FIG. 1
shows only one cylinder of a multi-cylinder engine, and that each
cylinder may similarly include its own set of intake/exhaust
valves, fuel injector(s), spark plug, etc.
[0023] FIG. 2 shows a schematic depiction of a vehicle's fuel
delivery system 210, exhaust system 212, and an air conditioning
system 214.
[0024] The fuel delivery system 210 may include a fuel tank 216
having a first port 218. A selectively permeable membrane 224 may
be used to separate the fuel tank into an upper portion 226 and a
lower portion 228, where the membrane may be enclosed by the fuel
tank. In this example, the first port may include a fuel cap 220, a
passage 222, and a valve (not shown), allowing fuel to be directed
into an upper portion 226 of the fuel tank 216. In other examples,
another suitable mechanism, allowing a fuel or a blended fuel
mixture to be directed into the upper portion of the fuel tank, may
be used.
[0025] The substances in the blended fuel mixture of the upper
portion may include gasoline and an alcohol, such as ethanol,
methanol, etc. In particular, fuel with various percentages of
ethanol may be delivered to the fuel tank. In some examples, a fuel
having 10% ethanol and 90% gasoline may be delivered to the fuel
tank. In other examples, a fuel having 85% ethanol and 15% gasoline
may be added to the fuel tank. Yet in other examples, alternative
substances may be used. The lower portion may also house a mixture,
such as an alcohol/water mixture.
[0026] The membrane 224 may include one or more membrane elements.
A membrane element can include a selectively permeable membrane
element that permits at least one component of a mixture to pass
through the membrane element from the upper portion to the lower
portion (or vice versa) at a greater rate than at least one other
component of the fuel mixture.
[0027] As one non-limiting example, the membrane element can be
configured to permit at least an alcohol component of a fuel
mixture to permeate through the membrane element from the upper
portion to the lower portion of the fuel tank. In this way, the
membrane element can provide a fuel separation function, whereby a
permeant includes a higher concentration of the alcohol component
and a lower concentration of the hydrocarbon component than the
initial fuel mixture due in part to the selectivity of the membrane
element, where the term permeant may be used herein to describe the
fuel component or components that permeate the membrane
element.
[0028] In one example, the rate of separation of an alcohol from a
gasoline/alcohol mixture in the upper portion may be affected by a
concentration of alcohol in a water/alcohol concentration in the
lower portion.
[0029] The membrane may be configured to provide increased surface
area for a given fuel tank size. The larger surface area allows a
greater amount of alcohol to be separated from the blended fuel
mixture, when desired. In this example, the membrane is pleated to
form an accordion-like structure. Additionally, the membrane may be
supported by a porous surface such as zirconia. In other examples,
the membrane may be honeycomb-shaped. Furthermore, the membrane may
include a number of different layers of membrane elements which may
assist in the separation performance.
[0030] In some examples, the membrane element may include a polymer
and/or other suitable material that permits an alcohol component to
permeate through the membrane element at a higher rate than a
hydrocarbon component. For example, the membrane element may
include polyethersulfone that contains both polar and nonpolar
characteristics, with the polar interaction dominant to an outer
section of the membrane element, which permits alcohol to permeate
the membrane element to a greater extent than the hydrocarbons.
Additionally or alternatively, membrane element may include a
nanofiltration material that utilizes molecule size exclusion
and/or chemical selectivity to separate an alcohol component from a
hydrocarbon component of a fuel mixture.
[0031] Additionally, in this example, flexible joints 229a and
229b, are coupled to the membrane, allowing the position of the
membrane to be passively adjusted as the volumes or relative
volumes of the fluids in both the upper and/or lower portion of the
fuel tank change. In this manner, the amount and/or relative
concentration of the various substances in the upper and/or lower
portion of the fuel tank can be adjusted during diffusion or during
refueling of the fuel tank, without requiring additional space in
the fuel tank. In alternate examples, the membrane may be actively
adjusted via a height adjustment mechanism (not shown) in response
to a change in the amount or relative concentration of the knock
suppressing substance(s) and/or gasoline in the upper and/or lower
portion of the fuel tank.
[0032] While the above example describes the membrane mounted in a
horizontal configuration, the membrane may also divide the tank in
a vertical configuration. In such a configuration, the membrane may
be substantially fixed.
[0033] A concentration sensor 230 and a fuel gage 231 may be
coupled to the upper portion of the fuel tank. The concentration
sensor may be configured to determine the concentration of one or
more substances in the fuel blended mixture enclosed by the upper
portion of the fuel tank. In other examples, a plurality of
concentration sensors may be located in the upper portion of the
fuel tank. Yet in other examples, an algorithm may be used to
determine the concentration of a specified substance in the blended
fuel mixture. In some examples, the concentration sensor 230 may be
positioned at a low point in the upper portion fuel tank, thereby
allowing measurement of the concentration of a specified substance
to be measured when only a small amount of fuel remains in the
upper portion of the fuel tank. Additional concentration sensors
(not shown) may be located in the lower portion of the fuel tank,
allowing the concentration of one or more substances in the lower
portion of the fuel tank to be determined.
[0034] Fuel gage 231 may be configured to determine the amount of
fuel in the upper portion of the fuel tank. In some examples, fuel
gage 231 may be a float type fuel gauge. In other examples, another
suitable type of gauge may be used that is capable of determining
the amount of fuel contained in one or both portions of the fuel
tank. Furthermore, an additional fuel gage (not shown) may be
located in the lower portion of the fuel tank, allowing the amount
of substances in the lower portion of the fuel tank to be
determined.
[0035] A second port 232 may be fluidly coupled to the lower
portion of the fuel tank, allowing a delivery of substances to the
lower portion of the fuel tank. In this example, the second port
may include a fuel cap 233, a passage 234, and a valve (not
shown).
[0036] The lower portion of the fuel tank may be fluidly coupled to
a fuel pump 236 by a fuel line 238. In this example, fuel pump 236
is electronically actuated by controller 12. Fuel pump 236 may be
coupled to a first fuel rail 240 by fuel line 242. The first fuel
rail may be coupled to a series of fuel injectors 244. In this
example, fuel injectors 244 inject fuel directly into the
combustion chambers of the engine 10. Further in this example, the
fuel injectors may include fuel injector 66, shown in FIG. 1.
However, in other examples, the fuel injectors may include port
fuel injectors and the number of injectors may be altered. The
timing of the fuel injection may be applied in such a way to
utilize the charge cooling effects of the mixture in the lower
portion, thereby reducing knock limits on engine operation.
[0037] Continuing with FIG. 2, the upper portion of the fuel tank
may be coupled to a fuel pump 246 by a fuel line 248. In this
example, fuel pump 246 is electronically actuated by controller 12.
The fuel pump 246 may be coupled to a second fuel rail 250 by fuel
line 252. In this example, the second fuel rail may be fluidly
coupled to a series of port fuel injectors 254. Further in this
example, one of the port fuel injectors may include fuel injector
67, shown in FIG. 1.
[0038] Continuing with FIG. 2, exhaust system 212, capable of
delivering water to the lower portion of the fuel tank, is fluidly
coupled to engine 10. The exhaust system may further include
emission control device 70 fluidly coupled to the engine via a duct
255. The emission control device may be fluidly coupled to
condenser 256 via duct 257. The condenser allows liquid water to be
collected from the exhaust stream. Fan 258 may be configured to
direct cooling air 260 over and around the condenser, affecting
liquid formation in the condenser. In alternate examples, the fan
may be removed and air generated by the vehicle's motion may be
directed over and around the condenser to provide cooling air for
condensation. Exhaust gases may exit the condenser through a
tailpipe 262.
[0039] A pump 266 may be fluidly coupled to the condenser by
conduit 264. Pump 266 may increase the pressure of the water in the
conduit, allowing water to be delivered to the lower portion of the
fuel tank. In other examples, a gravity fed system may be used to
deliver water to the lower portion of the fuel tank. A filter 268
may be coupled to pump 266 by conduit 270, allowing impurities to
be removed from the water collected in the condenser. A valve 275
may be fluidly coupled downstream of filter 268 and adjusted by
controller 12. Condenser 256, pump 266, filter 268, and valve 275
may be included in a water condensate system 276.
[0040] Additionally or alternatively, condensate from the air
conditioning system 214 may be collected and delivered to the lower
portion of the fuel tank through conduit 272, filter 268, and
conduit 274.
[0041] The fuel delivery system may be configured, under some
conditions, to adjust alcohol/water concentration in the lower
portion of the fuel tank, to thereby adjust not only the rate of
separation across the membrane, but also the freezing
characteristics of the mixture. For example, the amount of water
delivered to the lower portion of the fuel tank may be adjusted
responsive to operating conditions, thereby adjusting the
alcohol/water concentration, and thus the freezing characteristics
and/or the separation. The water delivered to the lower portion may
be adjusted in a variety of ways. These may include, for example,
adjusting valve 275, adjusting pump 266, adjusting cooling air 260,
adjusting operation of the air conditioning system, and/or
combinations thereof.
[0042] Various methods may be used to adjust the water delivered to
the fuel tank, such as shown in FIG. 3 and FIG. 4, for example.
[0043] Specifically, the following control method, shown in FIG. 3
and FIG. 4, may be implemented to adjust, and in some cases
increase, the rate of separation of an alcohol, such as ethanol,
from a blended fuel mixture in the upper portion of the fuel tank.
Additionally, the following control method may reduce degradation
or deterioration of the fuel delivery system, and increase the
efficiency of the engine. In particular, under some conditions, the
control method may reduce a possibility of freezing in the fuel
tank, lines, pumps, valves, etc.
[0044] Referring now specifically to FIG. 3, it shows a method 300
that may be implemented to adjust the rate of separation of an
alcohol in the fuel tank in response to a plurality of operating
conditions. The operating conditions may include: demand for knock
suppression, feedback from an engine knock sensor, ambient
temperature, pedal position, throttle position, exhaust
temperature, exhaust gas composition, etc.
[0045] At 312, an alcohol/water concentration in the lower portion
of the fuel tank is determined. In some examples, the concentration
may be indicated by at least one concentration sensor. In other
examples, the concentration may be inferred from various operating
parameters.
[0046] The method then proceeds to 314, where it is determined if
the concentration of the water in the lower portion of the fuel
tank is outside a desired range, e.g, a desired range for
controlling separation, while reducing changes for freezing. In
other examples, it may be determined if the concentration of
ethanol in the lower portion of the fuel tank is outside a desired
range. Yet in other examples, it may be determined if the amount of
water and/or ethanol in the lower portion of the fuel tank is
outside a desired range. In some examples, it may be determined
whether the concentration of water is above a threshold value, the
threshold value calculated during each iteration of method 300
based on various operating conditions, such as ambient temperature.
Additionally, the operating conditions may include: amount of fuel
in the fuel tank, engine speed, vehicle speed, engine load,
concentration of one or more substances in the blended fuel
mixture, requested torque, engine temperature, etc. As one specific
example, as the ambient temperature decreases, the threshold level
of water may decreased. As another specific example, as the ambient
temperature decreases, threshold level of ethanol may increase.
[0047] Further, the desired range of water and/or ethanol in the
lower portion may be adjusted based on a desired amount, or level,
of water and/or ethanol in the lower portion. In one example, the
water addition may be adjusted to provide sufficient levels of a
desired water/ethanol blend.
[0048] If it is determined that the concentration of water and/or
ethanol is in the desired range, the method ends.
[0049] Otherwise, the method proceeds to 316, where it is
determined if the ethanol and water mixture will freeze when
additional water is added to the ethanol/water mixture. In other
examples, it may be determined if the viscosity of the ethanol and
water mixture has increased beyond a threshold value. The
aforementioned determinations may take into account such parameters
as the ambient temperature, engine temperature, concentration of
water and/or ethanol, flowrate of ethanol water mixture through
injectors, and various others.
[0050] If it is determined that the mixture is subject to freezing
when additional water is added to the lower portion of the fuel
tank, the method proceeds to 318, where actions are taken to
inhibit the addition of water to the lower portion of the fuel
tank. The actions may include but are not limited to: at 318a,
shutting down operation of pump, at 318b, inhibiting airflow over
the condenser which may include stopping operation of fan 258 or
redirecting air away from the condenser, at 318c, closing valve
275, or combinations thereof. In other examples, at 318 actions may
be taken to decrease the amount of water delivered to the lower
portion of the fuel tank. After 318 the method returns to the
start.
[0051] If it is determined at 316 that the mixture is not subject
to freezing, the method then proceeds to 320, where it is
determined if the fuel tank capacity is large enough to accommodate
more water in the lower portion of the fuel tank. The
aforementioned determination may take into account such parameters
as fuel tank volume, position of the membrane, etc. If it is
determined that the fuel tank capacity is not large enough to
accommodate additional water, the method proceeds to 318, where
actions are taken to inhibit the addition of water to the lower
portion of the fuel tank.
[0052] However, if it is determined that the fuel tank capacity is
large enough to accommodate additional water in the lower portion
of the fuel tank the method proceeds to 322, where actions are
taken to add more water to the lower portion of the fuel tank.
These actions may include but are not limited to at 322a, driving
pump 266, at 322b, directing air over the condenser which may
include driving fan and/or redirecting air over and/or around the
condenser, and opening valve 275, at 322c. In this way, a control
method may be implemented to increase the rate of diffusion of a
knock suppressing substance when needed, while reducing degradation
of the fuel delivery system due to various parameters such as
temperature, fuel tank volume, and various others. After 322 the
method returns to the start.
[0053] In another example, as shown in FIG. 4, additional actions
may be added to method 300, shown in FIG. 3, which may inhibit
water from being added into the fuel tank when the addition of more
water will not promote more diffusion and/or when the state of
charge of a battery is below a threshold and thus may not be able
to power other systems in the vehicle. Method 400 may progress in a
similar approach to that shown in method 300. Similar acts are
labeled accordingly.
[0054] Now referring to FIG. 4, at 422 it is determined if the
addition of more water to the lower portion of the fuel tank will
promote more diffusion of the knock suppressing substance. If it is
determined that the addition of more water to the lower portion of
the fuel tank will not promote more diffusion, the method advances
to 318. However, if it is determined that the addition of more
water to the lower portion of the fuel tank will promote more
diffusion the method advances to 424. At 424 it is determined if
there is sufficient battery charge to operate the pump 266 and/or
fan 258, shown in FIG. 2, enabling water to be added to the lower
portion of the fuel tank. In other examples, it may be determined,
at 424, if the battery state of charge is above a predetermined
value which may take into account electrical power consumption of
the vehicle, ignition, and various other operations. If there
insufficient battery charge, the method proceeds to 318. Otherwise,
the method advances to 322.
[0055] In this way, control of condensate to the fuel tank is
adjusted responsive to the battery state of charge to reduce
battery load from the fans/pumps when the state of charge is low,
for example.
[0056] Note that the example control and estimation routines
included herein can be used with various engine and/or vehicle
system configurations. The specific routines described herein may
represent one or more of any number of processing strategies such
as event-driven, interrupt-driven, multi-tasking, multi-threading,
and the like. As such, various acts, operations, or functions
illustrated may be performed in the sequence illustrated, in
parallel, or in some cases omitted. Likewise, the order of
processing is not necessarily required to achieve the features and
advantages of the example embodiments described herein, but is
provided for ease of illustration and description. One or more of
the illustrated acts or functions may be repeatedly performed
depending on the particular strategy being used. Further, the
described acts may graphically represent code to be programmed into
the computer readable storage medium in the engine control
system.
[0057] It will be appreciated that the configurations and routines
disclosed herein are exemplary in nature, and that these specific
embodiments are not to be considered in a limiting sense, because
numerous variations are possible. For example, the above technology
can be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine
types. The subject matter of the present disclosure includes all
novel and nonobvious combinations and subcombinations of the
various systems and configurations, and other features, functions,
and/or properties disclosed herein. The following claims
particularly point out certain combinations and subcombinations
regarded as novel and nonobvious. These claims may refer to "an"
element or "a first" element or the equivalent thereof. Such claims
should be understood to include incorporation of one or more such
elements, neither requiring nor excluding two or more such
elements. Other combinations and subcombinations of the disclosed
features, functions, elements, and/or properties may be claimed
through amendment of the present claims or through presentation of
new claims in this or a related application. Such claims, whether
broader, narrower, equal, or different in scope to the original
claims, also are regarded as included within the subject matter of
the present disclosure.
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